Biocompatibility of two current adhesive resins

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Histopathology

Background:

• Biocompatibility assessment is crucial for dental restorative materials.
• Adhesive resins and calcium hydroxide cements are widely used in dental applications.
• Understanding the local tissue response to these materials is essential for clinical success.

Purpose of the Study:

• To evaluate and compare the biocompatibility of two adhesive resins (Clearfill Liner Bond 2 and Single Bond) and a calcium hydroxide cement (Dycal).
• To assess the inflammatory and healing responses of connective tissue to these dental materials over time.

Main Methods:

• Fifty-four polyethylene tubes filled with hand-mixed or light-cured dental materials were implanted into rat dorsal connective tissue.
• Histological analysis was performed at 7, 30, and 60 days post-implantation.
• Sections were stained with hematoxylin and eosin and evaluated under light microscopy for inflammatory cell infiltration and tissue reaction.

Main Results:

• Both adhesive resins induced moderate to intense inflammatory reactions at 7 days, which decreased but persisted with macrophage and giant cell involvement at 60 days.
• Thin fibrous capsule formation was observed around adhesive resins by 30 days.
• Calcium hydroxide cement (Dycal) showed complete healing with only a thin fibrous capsule by 30 days, indicating less irritation and better tissue tolerance.

Conclusions:

• Adhesive resins may elicit persistent local inflammatory reactions due to potential particulate release, questioning their biocompatibility in this context.
• Calcium hydroxide cement (Dycal) demonstrated superior biocompatibility compared to the tested adhesive resins.
• Connective tissue successfully encapsulated all tested materials, but the nature and persistence of the inflammatory response varied significantly.